So i delete the <meta name="description" content="<?php the_excerpt_rss(); ?>" /> from my head and let Yoast SEO do it.

In the SEO post titles, i add "%%focuskw%% %%excerpt%%" at the meta description. But i see that it does not recognize the auto generated text. It only shows the focuskeyword.

Is this because the auto generated term is not hard coded into the post itself? because its not. But <meta name="description" content="<?php the_excerpt_rss(); ?>" /> picks it up as if it were. How can i get Yoast SEO to pick it up as well?